Protein intake is an indispensable requirement for the growth and maintenance of any living creature. Every cell in our body needs protein to carry out any metabolism. The amount of protein required for a person, however, is variable depending on many factors, namely, body weight, age, physical activity, health condition, environment etc. Generally, protein intake should be in equilibrium with protein loss. Protein is lost in urine, feces, blood, sweat, skin, nails, hair etc. When protein intake is less than protein lost, it is called negative protein balance, whereas when it is the reverse it is called positive protein balance. Ideally, for normal adults a neutral protein balance should be attained.

Growing kids and pregnant and lactating women require more protein per unit weight than adults in normal condition and therefore they should be in positive protein balance. Growing kids and pregnant women actively gain muscle, bones, flesh and blood, and since for every cell in these tissues protein is a requirement, the recommended daily protein allowance is higher. Other conditions in which daily positive protein balance is needed include recovery stage after illness and when there is increased secretion of insulin, growth hormone, and testosterone.

As a general guideline, the recommended dietary allowance (RDA) for protein for adults is 0.8 grams per kilogram of body weight per day.

Table: Dietary Reference Intakes (DRIs): daily recommended intakes of protein for individuals. (Source: Food and Nutrition Board, Institute of Medicine)

Age, gender, life stage group	Protein DRI (grams/day)
Infants
0–6 mo	9.1
7–12 mo	13.5
Children
1–3 years	13
4–8 years	19
Adult Men
9–13 years	34
14–18 years	52
19–30 years	56
31–50 years	56
51–70years	56
> 70 years	56
Adult Women
9–13 years	34
14–18 years	46
19–30 years	46
31–50 years	46
51–70years	46
> 70 years	46
Pregnant Women
14–18 years	71
19–30 years	71
31–50 years	71
Lactating Women
14–18 years	71
19–30 years	71
31–50 years	71

Note: Daily Reference Intakes (DRIs) have been developed, since 1996 by the Food and Nutrition Board, Commission on Life Sciences, National Research Council, to replace the Recommended Dietary Allowances (RDAs).

Protein related articles:
Protein: Health benefit, Digestion, and Deficiency
Food Protein Sources: Animal and Vegetable Sources High or Low in Protein
Soybean/tofu: nutritional value and health benefits
Essential and non essential amino acids: Definitions and Functions
L-Arginine: Food Sources, Health Benefits and Side Effects

 

References

Hamilton, E. M. N., Whitney, E. N., and Sizer, F. S. 1991. Nutrtion: Concepts and Controversies, 5th ed. West Publishing Co.,New York, USA.

Institute of Medicine. 2005. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academy Press. (Food and Nutrition Board, Institute of Medicine, National Academies).